Temperature control



8- s 1942- J. W. MILLER TEMPERATURE CONTROL Filed Sept. 18, 1940INVENTOR.

JOHN 14/. M/LLEE Patented Aug. 4, 1942 2,292,082 TEMPERATURE CONTROLJohn w. Miller,

Lansing/Mich assignor to Hotor Wheel Corporation, Lansing, Mich, acorporation ofMichigan Application September 18, 1940, SerialPic-357,214 1 Claim. (Cl. 236-) This invention relates to a novel damperfor use with combustion apparatus, and to the combination of such adamper with a heater having an air tube and fan for the discharge ofheated air from the heater.

Ordinary circulating type space heaters usually have not been equippedwith fans for aiding the circulation of heat. There is a growingtendency toward providing fans for such heaters as their use permits themore even distribution of heat throughout the room to be heated. The airthat is blown out of the heater by the fan may be cold when the heateris first put into operation. Moving cold air is decidedly uncomfortableif it strikes a person in the room to be heated.

Itis the primary object of this invention to provide a novelthermostatically controlled damper for automatically maintaining the airexpelled from the heater by the fan between substantially constantpredetermined temperature limits, within the range of human comfort.

Another object of the invention is to provide an automatic control ofvthe type mentioned whichcan be regulated manually so as not to interferewith the circulation of cool air by the fan when desired.

Still another object of the invention is to provide a thermostaticallyoperated damper of simple construction which is economically fabricatedand assembled.

A stiii further object is the provision of a forced air circulating unitfor a heater in which a thermostatically controlled damper isincorpcrated.

These objects will more fully appear in thefoilowing specification whenread in connection with the accompanying drawing, wherein:

Figure l-is a side elevational view of a circulating heater embodyingthe invention, parts being broken away to show the interior of theheater;

Figure 2 is a fragmentary cross-sectional view taken on substantiallythe line 2-2 of Figure 1;

Figure 3 is a perspective view of the air control itself;

Figure 4 is a fragmentary end elevatlonal view of the air tube showingthe control knob and its retainer; and

Figure 5 is an end elevational view of the thermostatic element foroperating the air control.

Referring now more particularly tothe drawing, the inventionis shown asembodied in a room heater of the circulating type. In general the heatercomprises a heat exchanger Ill, and

an outer casing ll surrounding the heat exchanger in spaced relation tothe walls thereof, the casing having in a side panel thereof an air tubel2 in which is incorporated the air control. The heat exchanger Illconsists of a cylindrical steel shell having a burner ii of thevaporizing pot type positioned in its lower end. Connected to the burnerby means of a short pipe H is a fuel metering device IS. The latter isconnected by means of a pipe IE to a suitable source of fuel supply.Adjacent the upper end of the heat exchanger is a flue outlet I1. I

The outer casing ll consists of four corner posts IS, a top wall attheir upper ends, and

panels 22 intermediate the corner posts. The

panels 22 terminate a short distance above the lower ends of the cornerposts. Thus, the lower end of the casing II is open to admit cool airfrom the floor to the burner l3 and to the space between the heatexchanger ill and the outer casing II. The panels 22 are provided withlouvres l8 through which air may circulate.

One of the side panels 22 includes as a part thereof a hinged door 23.The hinged door 23 has an oval opening therein defined by a flange 23ainto which is secured the air tube l2. The air tube I2 is made up of twosheet metal stampings 25 and 25. The inner stamping 25 is rela-- tivelydeeply dished and has a peripheral flange 25a. The outer stamping 26 hasa peripheral flange 26a. The two flanges 25a and 26a are nested togetherand fitted against the flange 2311. See Figure 2. All three flanges arewelded or otherwise secured together.

The air tube is provided with an inlet opening 2'! and an outlet opening28. The former is near the upper end of the inner stamping 25. Theopening 28 is near the lower end of the outer stamping 26 and is definedby a flange 28a. A grille 29 having a plurality of louvres 30 isrotatably mounted on the flange 28a. The grille is provided with knobs3i by which it can be rotated.

Mounted on the stamping 26 at its upper end is an electric motor 32. Theshaft 33 of the motor extends through the stamping 26 into the interiorof the air tube l2 and carries a centrifugal fan 34. The centrifugal fan34 is located with its inlet adjacent the inlet opening 21 in the tubel2.

Extending transversely of the air tube is a.

shaft 35. The shaft is rotatably mounted in bearings in the oppositesides of the inner stamping 25. A damper 35 is rotatably mounted uponthe shaft 35. The damper is of substantially the same shape and area asthe horizontal crosssection of the air tube I 2. One end of the damperis provided with a rectangular notch 3?. Into this notch 3! a spiralthermostatic element 38 is placed, as best shown in Figure 3. One end ofthe thermostatic element 38 is attached to the damper 36 by a rivet 4|.The other end of the thermostatic element extends through a slot in theadjacent end of the shaft 35 and is thereby held against rotationrelative thereto.

An adjusting knob 39 is securely attached to the end of the shaft 35opposite the thermostatic element 38. The knob 39 is located outside ofthe air tube l2 and between the panel 22 and the heat exchanger M. Aresilient latch 40 is attached to the exterior of the adjacent side wallof the air tube. This latch 40 frictionally engages the knob 39 andholds it in any position in which the knob is set. Preferably the knobis provided with indicia such as the letters S and (see Figure 4) whichcooperate with the latch 40 functioning as a pointer, to indicate thesetting of the damper 36.

Under normal operating conditions in cold weather when the circulatingheater is employed to furnish heat to th room, the knob iS adjusted sothat either letter S is adjacent the latch 40. When so adjusted thedamper will be shut if the burner is cold. Thus, when the burner isfirst ignited, or is operating at its lowest stage of operation, the fan34 may be switched on and no air will be discharged from the air tube.Any heat generated by the burner will rise directly through the casingtoward the ceiling of the room.

I When the metering device 15 is adjusted so as to increase the flow offuel to the burner, combustion will proceed at a faster rate and moreheat will be generated by the heat exchanger. The increased heat willact upon the thermostatic element 38 causing it to expand and rotate thedamper 36 on the shaft 35 toward its open position. The fan 34 will thenpick up a certain quantity of air, depending upon how far the damper 36is open, and force it through the airtube l2 into th room. A stillfurther increase in the fuel supply will produce more heat, therebyopening the damper still further. Eventually the damper will opencompletely. It will be obvious, therefore, that as the heat exchangerbecomes hotter, more air can be passed through the air tube and stillmaintain a reasonably high temperature therein. By employing athermostatic element which has the proper operating characteristics, thedamper can be made to maintain the air emanating from the air tub at asubstantially constant temperature.

' for circulating air within the room even though 7 the air in the roomand maintain a cooler and consequently more comfortable temperature.When it is desired to operate th fan as a means the burner is cold, theshaft 35 may be rotated by means of the knob 39 through an angle of 90degrees from its shut position. In other words, one of the letters 0will be placed adjacent the latch 40. This maybe easily accomplished byopening the door 23 to gain access to the knob 39 and thereafterrotating the latter the desired amount. 01' course, when the heatexchanger I0 is cold, the temperature of the air passing through the airtube I2 is so low as to have no appreciable effect upon the thermostaticelement From the foregoing it will be evident that this inventionprovides an automatic control whereby the temperature of air circulatedby a fan in a space heater may be maintained substantially constant. Italso provides a means for permit ting cold air to be circulated by thefan if desired.

The scope of the invention is indicated in the appended claim.

A unitary air circulator of a character suitable for use with a sourceof external heat which comprises an elongated air tube having an inletopening at one end thereof for admission thereto of heated air and anoutlet opening at the other end for the discharge of heated air, a fandisosed within the tube adjacent one Of said openings for circulatingair through said tube, a

motor outside of the tube and connected to the fan for operating thefan, a damper disposed within the tube between said openings, said Idamper being adjustable to control the volume of air circulated throughsaid tube, said damper comprising a damper blade rotatably mounted on. ashaft, thermostatic means connected to said "blade and shaft forrotating said blade on said shaft to open or close the damper inresponse to an increase or decrease respectively in the temperature ofthe air within the tube, said shaft being rotatably connected to saidair tube to permit adjustment of said damper blade within said,

tube independently of its adjustment by said thermostatic means, saidfan, damper and thermostat constituting the only apparatus within thetube.

JOHN W. MILLER.

